Digitally controlled filter tuning for WLAN communication devices

Abstract

A digitally controlled filter tuning method and corresponding WLAN (Wireless Local Area Network) communication devices and integrated circuit chips are provided. A WLAN communication signal is filtered by a tunable filter. A cut-off frequency of the tunable filter is tuned by a feedback loop. Tuning the cut-off frequency includes comparing by a comparator an output signal emitted by the tunable filter to a reference signal and emitting by the comparator a comparator signal indicative of the difference between the output signal and the reference signal. Further, tuning the cut off frequency comprises receiving the comparator signal by a tuning controller and setting by the tuning controller the cut-off frequency of the tunable filter based on the comparator signal by applying a digital tuning word to the tunable filter. The described filter tuning technique may reduce product and manufacturing costs while providing enhanced tuning accuracy.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to WLAN (Wireless Local Area Network) communication devices and corresponding methods and integrated circuit chips, and in particular to the filter tuning in such WLAN communication devices.[0003]2. Description of the Related Art[0004]A wireless local area network is a flexible data communication system implemented as an extension to, or as an alternative for, a wired LAN. Using radio frequency or infrared technology, WLAN systems transmit and receive data over the air, minimizing the need for wired connections. Thus, WLAN systems combine data connectivity with user mobility.[0005]Today, most WLAN systems use spread spectrum technology, a wideband radio frequency technique developed for use in reliable and secure communication systems. The spread spectrum technology is designed to trade off bandwidth efficiency for reliability, integrity and security. Two types of spread spectrum radio syst...

AI Technical Summary

Benefits of technology

[0012]An improved filter tuning method and corresponding WLAN communication devices and integrated circuit chips are provided that may overcome the disadvantages of the conventional approaches. In particular, embodiments may allow for lowering the power consumption caused by the tuning circuitry. Other embodiments offer the advantage of reduced product and manufacturing costs. In further embodiments, the achievable communication data rate is increased. In still other embodiments, filter tuning accuracy is enhanced.

Problems solved by technology

However, substantial additional circuitry is required for implementing the master-slave tuning technique.

Therefore, conventional WLAN communication devices often suffer from the problem of increased power consumption.

In addition, those WLAN communication devices have the disadvantage of causing high manufacturing and product costs.

Yet, since filtering of the communication signal is interrupted while the filter cut-off frequency is being tuned, prior art WLAN communication devices applying the self-tuning technique often have difficulties in achieving efficient data rates.

Further, the filtering accuracy in those devices is decreased due to, e.g., cut-off frequency drift, during the time interval between the individual tuning interruptions.

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